1. Field of the Invention
The present invention relates to a semiconductor device manufacturing method, a target substrate processing system, and a storage medium, and particularly to a method for manufacturing semiconductor devices that include a copper-containing conductive film, and a system for processing a target substrate and a storage medium for the same.
2. Description of the Related Art
In recent years, semiconductor devices employ multi-layered structures including interconnection lines stacked one above the other, so as to increase the operation speed and to decrease the size. In order to increase the operation speed, it is necessary to decrease the resistivity of interconnection lines and the electric capacitance between interconnection lines. For this reason, copper (Cu), which is low in resistivity, is widely used for interconnection lines, while a low dielectric constant insulation film (Low-k film) is widely used for interlayer insulation films between Cu interconnection lines to decrease the capacitance between the Cu interconnection lines.
However, in a case where a Cu interconnection line is formed by use of a damascene method, when etching of an interlayer insulation film and ashing of a photo-resist are performed, the surface layer of the Cu interconnection line exposed at the bottom of an interconnection groove or via-groove is partly etched. The Cu particles thus generated by etching are generally deposited on the side surface of the interlayer insulation film inside the groove or the upper surface of the interlayer insulation film. If a heat process or electric field is applied to the structure with Cu deposits present thereon, Cu may be diffused into the interlayer insulation film. Cu thus diffused into the interlayer insulation film lowers the yield of semiconductor devices.
In general, wet cleaning is performed to remove Cu deposits present on interlayer insulation films.
However, where an interlayer insulation film is formed of a Low-k film, the Low-k film may absorb moisture in wet cleaning and increase the dielectric constant. Accordingly, it is not preferable to perform wet cleaning in a state where a Low-k film is exposed.
A water vapor process other than wet cleaning has been proposed, (Jpn. Pat. Appln. KOKAI Publications No. 2001-271192), but this process may also increase the dielectric constant of Low-k films due to the presence of water (H2O).
A method for removing Cu deposits by organic acid dry cleaning is known (Jpn. Pat. Appln. KOKAI Publications No. 2005-330546), but dry cleaning that merely uses an organic acid gas cannot provide the effect of removing Cu deposits comparable to wet cleaning, unless the Cu deposits have been oxidized.
Further, a method for removing copper deposits while supplying acetic acid vapor and water vapor or supplying oxygen is known (Jpn. Pat. Appln. KOKAI Publications No. 2001-271192), but the water vapor may increase the dielectric constant of Low-k films, as described, and oxygen may increase the interconnection line resistance due to oxidation of underlying Cu layers.